nmates say their reasons for converting include the protection of belonging to a gang and perceived material perks offered to Muslims.

The report also claimed many of the prisoners surveyed felt that as a Muslim they were entitled to more time outside of their cells and better food at Ramadan.

Staff at one high security prison said non-Muslims were pressured into converting and adopting a 'strict' form of Islam.

Chief Inspector Dame Anne Owers also warned of the need for greater engagement with Muslim prisoners to prevent them turning to extremism.

Her report said attempts to crack down on Muslim fanatics in jail are pushing inmates into the arms of extremists, claiming prison staff treat all Muslims - including converts - as if they could pose a security threat.

But this 'blanket approach' risks turning moderates into radicals.

There are 10,300 Muslim prisoners in jails in England and Wales. The number has increased fourfold since 1994.

Less than 1 per cent are behind bars for terror-related offences. Those who are include radical preacher Abu Hamza, who is awaiting extradition to the U.S.